The present invention relates to telescoping seating systems; and more particularly, it relates to improvements in row assemblies for telescoping seating systems.
A telescoping seating system includes a number of row assemblies which may be extended for use or retracted for storage. In the use position, the row assemblies are arranged in tiered or stepped relation. In the storage position, the row assemblies are arranged in superposed relation--i.e., a lower row is nested beneath the next higher row. Such telescoping seating systems are used in gymnasiums, auditoriums and the like; and they may have seating arrangements of the bleacher type, such as are disclosed in co-owned U.S. Pat. Nos. 3,667,171 and 3,768,215, or they may be of the platform and individual folding chair type such as is disclosed in co-owned application Ser. No. 349,959, of Vance, et al, filed Apr. 11, 1973. The present invention may be adapted to either the bleacher type of seating arrangement or the chair platform type, as will be disclosed below. Other seating structures may be found in U.S. Pat. Nos. 2,898,639, 3,335,533, 3,107,398, 3,107,399, 3,222,827, 3,478,473, 3,748,798, and 3,768,215.
In general, each row assembly includes posts which are mounted to floor-engaging wheel carriages or channels. The tops of the posts for each row are connected together to form a rigid frame or understructure by a deck which may include a riser beam or, in the case of low-rise platforms, a tread panel frame.
As used herein, the word "telescope" thus refers to seating systems of the type in which individual row assemblies may be moved to a nested position beneath a next higher row, so that the wheel channels are moved side-by-side in the retracted position and the overall depth of the system when retracted may be made equal to the depth of a single row. This is to be distinguished from some prior systems, in which the wheel channels are aligned in front of one another. The latter systems, of course, have limitations on the depth of the system when retracted for storage.
Typically, in prior systems, a pair of posts support a single row section; and they have been arranged to be vertical. For telescoping systems, the wheel carriages (and, hence, the posts) are located progressively further out from the center of the row for the higher rows so that all of the carriages will nest into side-by-side relation when the system is telescoped into the storage position. In some systems, a riser member or beam is connected by fasteners such as bolts to the top of a pair of posts for each row; and the tread panel or platform is supported by support arms or cantilever members connected to and extending outwardly from the riser beam. In other systems, as mentioned, a rigid frame is used for the deck and it is directly connected to the posts. The tread panels may or may not form a structural element of such a deck.
Because the posts in the prior art structures are vertical and spaced at different intervals from row to row, the center span and cantilever span varies from row to row so that materials have to be strengthened and structure added in order to account for the "worst case" spans for all rows. Further, in these structures it has been necessary to form apertures in the riser members and cover materials (such as tread panels and seat boards) for attaching bolts at varying distances during manufacture, thereby requiring that each row, in effect, have a unique design. This problem is further troublesome because the telescoping seating systems are shipped from a manufacturer to a job site in disassembled condition. Thus, workmen at the site must sort out and group associated riser beams, posts, bracing, and cover materials. Bracing between the riser beams and posts or columns of the prior art normally varies according to whether a given row is one of the lower rows, one of the intermediate rows or one of the upper rows, as will be discussed more fully within.
In a preferred form of the present invention, all row assemblies have similar ` deck/support post configurations`. By this is meant that the included angles between the post and the horizontal plane of the tread panel of all the row assemblies are equal and the included angles between the posts and the floor are equal, the only differences in such configurations being that the posts are different lengths depending upon the position of the row in the system. Looking from the front or back, the axis of the post intersects with the horizontal plane of the tread panel. These intersections are vertically aligned at each side of the rows so that the center span for all rows is the same. Each of the `deck/support post configurations` define with the floor an isoceles trapezoid, and the angles of any one of such trapezoids is equal to the other corresponding angles of the other trapezoids.
This is accomplished in the illustrated embodiment by orienting the posts to an off-vertical position. Specifically, the posts for each row are inclined inwardly (i.e., toward each other) in a uniform manner. Thus, all posts on either side of the structure are parallel. The connections between the posts and their associated decks (i.e., the deck/post connections) are in vertical alignment for each side of the system. Thus, all decks have the same distances between connections to posts and the bolt aperture are at the same locations for each riser, seat board and tread panel. This on-line hole location permits uniform fabrication of risers and cover materials at the manufacturer's site, and obviates the need to code them during manufacture or to sort them during installation.
The present invention has still another important advantage: because the distance between deck/post connections is the same for all row assemblies, the simple beam loading or "center span" as well as the end loading or "cantilever span" is the same for all rows. It will be observed that the center span is determined by the location of attachment to the posts, not necessarily to the decks if intermediate members or brackets are used to make the connection. This permits the elimination of secondary members to support the center span as the wheel carriages become spaced further apart, as required in the prior art. Simple tension members extending between the posts may be employed. Such tension members may take the form of flat steel straps, as distinguished from the heavy angle-iron compression members used as secondary support members in prior designs.
Because the spacing of wheel carriages with the present invention is the same as for the corresponding row of a prior art system having similar rise and span, the same safety precautions are available to prevent overturning or resist sway under similar loading. It is believed that resistance to side sway is even improved with the present design, as will be discussed within.
There are retractable seating structures in the prior art which achieve a constant span, but these are not "telescoping" systems within the strict meaning of that term as defined herein. Such prior systems are referred to herein as "folding" seating systems. In such folding systems the posts are aligned in the fore-and-aft direction (i.e., parallel to the direction in which the rows are moved for use); and the wheel carriages are offset relative to wheel carriages for adjacent rows to avoid interference with each other. Such systems obviously do not retract to a depth which is equal to the depth of a single row, as is the case in telescoping seating systems (because the posts assume a side-by-side relation in the nested position). This is so in the case of folding systems because the posts are forwardly aligned in the manner described; and they would interfere with one another.
Some telescoping systems have also achieved on-line drilling of holes in the risers and cover materials with vertical posts. In these systems, brackets are used to interconnect the posts with a row support frame. A bracket is connected to all row support frames at the same locations, but the posts are located progressively outwardly for higher rows and the brackets are provided with a number of post connection locations to accommodate the variation in spacing as the posts are spaced increasingly further apart. Thus, even though constant spacing for hole drilling is achieved, the structural shortcomings of the prior art are still present--namely, a variation in center span and cantilever span.
In its broader aspects, then, the present invention is directed to a telescoping seating structure which has a similar deck/support post configuration in all rows. This uniformity facilitates manufacture and assembly (by permitting on-line hole-drilling in risers and cover materials), and achieves a constant center span for all rows.
Once a uniform deck/support post configuration is achieved, the internal stresses on the structure are the same for all rows-- that is, the elements of the structure carry the same load (for the same loading conditions) irrespective of the position of the row in the system. This obviously was not true in prior telescoping seating systems of varying center span, such as has been discussed.
It is known that a desirable design in a theoretical sense would have one-half the length of a row in the center span and one-quarter of the length in each of the cantilever spans. This is also made possible for all rows with the present invention.
Other features and advantages of the present invention will be apparent to persons skilled in the art from the following detailed description of a preferred embodiment accompanied by the attached drawing, wherein identical reference numerals will refer to like parts in the various views .